From b6243e7d1fa1354f1eb19b731d61ce31c969ca12 Mon Sep 17 00:00:00 2001
From: elsid <elsid.mail@gmail.com>
Date: Fri, 8 Mar 2019 15:02:49 +0300
Subject: [PATCH 1/7] Fix name styleguide

---
 components/detournavigator/navmeshtilescache.cpp | 14 +++++++-------
 components/detournavigator/navmeshtilescache.hpp |  2 +-
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/components/detournavigator/navmeshtilescache.cpp b/components/detournavigator/navmeshtilescache.cpp
index 64edab0ad..418e69e82 100644
--- a/components/detournavigator/navmeshtilescache.cpp
+++ b/components/detournavigator/navmeshtilescache.cpp
@@ -62,8 +62,8 @@ namespace DetourNavigator
             return Value();
 
         // TODO: use different function to make key to avoid unnecessary std::string allocation
-        const auto tile = tileValues->second.Map.find(makeNavMeshKey(recastMesh, offMeshConnections));
-        if (tile == tileValues->second.Map.end())
+        const auto tile = tileValues->second.mMap.find(makeNavMeshKey(recastMesh, offMeshConnections));
+        if (tile == tileValues->second.mMap.end())
             return Value();
 
         acquireItemUnsafe(tile->second);
@@ -96,7 +96,7 @@ namespace DetourNavigator
 
         const auto iterator = mFreeItems.emplace(mFreeItems.end(), agentHalfExtents, changedTile, navMeshKey);
         // TODO: use std::string_view or some alternative to avoid navMeshKey copy into both mFreeItems and mValues
-        const auto emplaced = mValues[agentHalfExtents][changedTile].Map.emplace(navMeshKey, iterator);
+        const auto emplaced = mValues[agentHalfExtents][changedTile].mMap.emplace(navMeshKey, iterator);
 
         if (!emplaced.second)
         {
@@ -125,16 +125,16 @@ namespace DetourNavigator
         if (tileValues == agentValues->second.end())
             return;
 
-        const auto value = tileValues->second.Map.find(item.mNavMeshKey);
-        if (value == tileValues->second.Map.end())
+        const auto value = tileValues->second.mMap.find(item.mNavMeshKey);
+        if (value == tileValues->second.mMap.end())
             return;
 
         mUsedNavMeshDataSize -= getSize(item);
         mFreeNavMeshDataSize -= getSize(item);
         mFreeItems.pop_back();
 
-        tileValues->second.Map.erase(value);
-        if (!tileValues->second.Map.empty())
+        tileValues->second.mMap.erase(value);
+        if (!tileValues->second.mMap.empty())
             return;
 
         agentValues->second.erase(tileValues);
diff --git a/components/detournavigator/navmeshtilescache.hpp b/components/detournavigator/navmeshtilescache.hpp
index 7418c4d3a..e244cda9d 100644
--- a/components/detournavigator/navmeshtilescache.hpp
+++ b/components/detournavigator/navmeshtilescache.hpp
@@ -108,7 +108,7 @@ namespace DetourNavigator
 
         struct TileMap
         {
-            std::map<std::string, ItemIterator> Map;
+            std::map<std::string, ItemIterator> mMap;
         };
 
         std::mutex mMutex;

From 14c9190f490956ae86f01ff79c7fe488247d76cf Mon Sep 17 00:00:00 2001
From: elsid <elsid.mail@gmail.com>
Date: Fri, 8 Mar 2019 15:06:11 +0300
Subject: [PATCH 2/7] Move tile replacement into separate function

---
 components/detournavigator/makenavmesh.cpp | 84 ++++++++++++----------
 1 file changed, 45 insertions(+), 39 deletions(-)

diff --git a/components/detournavigator/makenavmesh.cpp b/components/detournavigator/makenavmesh.cpp
index f1f6205c7..5b3923006 100644
--- a/components/detournavigator/makenavmesh.cpp
+++ b/components/detournavigator/makenavmesh.cpp
@@ -461,6 +461,49 @@ namespace
             ++power;
         return power;
     }
+
+    dtStatus addTile(dtNavMesh& navMesh, const NavMeshData& navMeshData)
+    {
+        const dtTileRef lastRef = 0;
+        dtTileRef* const result = nullptr;
+        return navMesh.addTile(navMeshData.mValue.get(), navMeshData.mSize,
+                               doNotTransferOwnership, lastRef, result);
+    }
+
+    dtStatus addTile(dtNavMesh& navMesh, const NavMeshTilesCache::Value& cachedNavMeshData)
+    {
+        const dtTileRef lastRef = 0;
+        dtTileRef* const result = nullptr;
+        return navMesh.addTile(cachedNavMeshData.get().mValue, cachedNavMeshData.get().mSize,
+                               doNotTransferOwnership, lastRef, result);
+    }
+
+    template <class T>
+    UpdateNavMeshStatus replaceTile(const SharedNavMeshCacheItem& navMeshCacheItem,
+        const TilePosition& changedTile, T&& navMeshData)
+    {
+        const auto locked = navMeshCacheItem.lock();
+        auto& navMesh = locked->getValue();
+        const int layer = 0;
+        const auto tileRef = navMesh.getTileRefAt(changedTile.x(), changedTile.y(), layer);
+        unsigned char** const data = nullptr;
+        int* const dataSize = nullptr;
+        const auto removed = dtStatusSucceed(navMesh.removeTile(tileRef, data, dataSize));
+        const auto addStatus = addTile(navMesh, navMeshData);
+
+        if (dtStatusSucceed(addStatus))
+        {
+            locked->setUsedTile(changedTile, std::forward<T>(navMeshData));
+            return makeUpdateNavMeshStatus(removed, true);
+        }
+        else
+        {
+            if (removed)
+                locked->removeUsedTile(changedTile);
+            log("failed to add tile with status=", WriteDtStatus {addStatus});
+            return makeUpdateNavMeshStatus(removed, false);
+        }
+    }
 }
 
 namespace DetourNavigator
@@ -583,47 +626,10 @@ namespace DetourNavigator
             if (!cachedNavMeshData)
             {
                 log("cache overflow");
-
-                const auto locked = navMeshCacheItem.lock();
-                auto& navMesh = locked->getValue();
-                const auto tileRef = navMesh.getTileRefAt(x, y, 0);
-                const auto removed = dtStatusSucceed(navMesh.removeTile(tileRef, nullptr, nullptr));
-                const auto addStatus = navMesh.addTile(navMeshData.mValue.get(), navMeshData.mSize,
-                                                       doNotTransferOwnership, 0, 0);
-
-                if (dtStatusSucceed(addStatus))
-                {
-                    locked->setUsedTile(changedTile, std::move(navMeshData));
-                    return makeUpdateNavMeshStatus(removed, true);
-                }
-                else
-                {
-                    if (removed)
-                        locked->removeUsedTile(changedTile);
-                    log("failed to add tile with status=", WriteDtStatus {addStatus});
-                    return makeUpdateNavMeshStatus(removed, false);
-                }
+                return replaceTile(navMeshCacheItem, changedTile, std::move(navMeshData));
             }
         }
 
-        const auto locked = navMeshCacheItem.lock();
-        auto& navMesh = locked->getValue();
-        const auto tileRef = navMesh.getTileRefAt(x, y, 0);
-        const auto removed = dtStatusSucceed(navMesh.removeTile(tileRef, nullptr, nullptr));
-        const auto addStatus = navMesh.addTile(cachedNavMeshData.get().mValue, cachedNavMeshData.get().mSize,
-                                               doNotTransferOwnership, 0, 0);
-
-        if (dtStatusSucceed(addStatus))
-        {
-            locked->setUsedTile(changedTile, std::move(cachedNavMeshData));
-            return makeUpdateNavMeshStatus(removed, true);
-        }
-        else
-        {
-            if (removed)
-                locked->removeUsedTile(changedTile);
-            log("failed to add tile with status=", WriteDtStatus {addStatus});
-            return makeUpdateNavMeshStatus(removed, false);
-        }
+        return replaceTile(navMeshCacheItem, changedTile, std::move(cachedNavMeshData));
     }
 }

From 0c16fef285bdccee912887c9a027f2d4b773636c Mon Sep 17 00:00:00 2001
From: elsid <elsid.mail@gmail.com>
Date: Fri, 8 Mar 2019 15:06:47 +0300
Subject: [PATCH 3/7] Add navmesh update status builder

---
 .../detournavigator/asyncnavmeshupdater.cpp   |  4 +-
 components/detournavigator/makenavmesh.cpp    | 56 ++++++++++++++-----
 components/detournavigator/makenavmesh.hpp    | 10 ++--
 3 files changed, 50 insertions(+), 20 deletions(-)

diff --git a/components/detournavigator/asyncnavmeshupdater.cpp b/components/detournavigator/asyncnavmeshupdater.cpp
index 1e158667b..fd240e4a0 100644
--- a/components/detournavigator/asyncnavmeshupdater.cpp
+++ b/components/detournavigator/asyncnavmeshupdater.cpp
@@ -32,11 +32,11 @@ namespace DetourNavigator
     {
         switch (value)
         {
-            case UpdateNavMeshStatus::ignore:
+            case UpdateNavMeshStatus::ignored:
                 return stream << "ignore";
             case UpdateNavMeshStatus::removed:
                 return stream << "removed";
-            case UpdateNavMeshStatus::add:
+            case UpdateNavMeshStatus::added:
                 return stream << "add";
             case UpdateNavMeshStatus::replaced:
                 return stream << "replaced";
diff --git a/components/detournavigator/makenavmesh.cpp b/components/detournavigator/makenavmesh.cpp
index 5b3923006..a03e9fd8d 100644
--- a/components/detournavigator/makenavmesh.cpp
+++ b/components/detournavigator/makenavmesh.cpp
@@ -441,17 +441,47 @@ namespace
         return NavMeshData(navMeshData, navMeshDataSize);
     }
 
-    UpdateNavMeshStatus makeUpdateNavMeshStatus(bool removed, bool add)
+    class UpdateNavMeshStatusBuilder
     {
-        if (removed && add)
-            return UpdateNavMeshStatus::replaced;
-        else if (removed)
-            return UpdateNavMeshStatus::removed;
-        else if (add)
-            return UpdateNavMeshStatus::add;
-        else
-            return UpdateNavMeshStatus::ignore;
-    }
+    public:
+        UpdateNavMeshStatusBuilder() = default;
+
+        UpdateNavMeshStatusBuilder removed(bool value)
+        {
+            if (value)
+                set(UpdateNavMeshStatus::removed);
+            else
+                unset(UpdateNavMeshStatus::removed);
+            return *this;
+        }
+
+        UpdateNavMeshStatusBuilder added(bool value)
+        {
+            if (value)
+                set(UpdateNavMeshStatus::added);
+            else
+                unset(UpdateNavMeshStatus::added);
+            return *this;
+        }
+
+        UpdateNavMeshStatus getResult() const
+        {
+            return mResult;
+        }
+
+    private:
+        UpdateNavMeshStatus mResult = UpdateNavMeshStatus::ignored;
+
+        void set(UpdateNavMeshStatus value)
+        {
+            mResult = static_cast<UpdateNavMeshStatus>(static_cast<unsigned>(mResult) | static_cast<unsigned>(value));
+        }
+
+        void unset(UpdateNavMeshStatus value)
+        {
+            mResult = static_cast<UpdateNavMeshStatus>(static_cast<unsigned>(mResult) & ~static_cast<unsigned>(value));
+        }
+    };
 
     template <class T>
     unsigned long getMinValuableBitsNumber(const T value)
@@ -494,14 +524,14 @@ namespace
         if (dtStatusSucceed(addStatus))
         {
             locked->setUsedTile(changedTile, std::forward<T>(navMeshData));
-            return makeUpdateNavMeshStatus(removed, true);
+            return UpdateNavMeshStatusBuilder().added(true).removed(removed).getResult();
         }
         else
         {
             if (removed)
                 locked->removeUsedTile(changedTile);
             log("failed to add tile with status=", WriteDtStatus {addStatus});
-            return makeUpdateNavMeshStatus(removed, false);
+            return UpdateNavMeshStatusBuilder().removed(removed).getResult();
         }
     }
 }
@@ -565,7 +595,7 @@ namespace DetourNavigator
             const auto removed = dtStatusSucceed(navMesh.removeTile(tileRef, nullptr, nullptr));
             if (removed)
                 locked->removeUsedTile(changedTile);
-            return makeUpdateNavMeshStatus(removed, false);
+            return UpdateNavMeshStatusBuilder().removed(removed).getResult();
         };
 
         if (!recastMesh)
diff --git a/components/detournavigator/makenavmesh.hpp b/components/detournavigator/makenavmesh.hpp
index 55d3e261c..20198047c 100644
--- a/components/detournavigator/makenavmesh.hpp
+++ b/components/detournavigator/makenavmesh.hpp
@@ -20,12 +20,12 @@ namespace DetourNavigator
     class RecastMesh;
     struct Settings;
 
-    enum class UpdateNavMeshStatus
+    enum class UpdateNavMeshStatus : unsigned
     {
-        ignore,
-        removed,
-        add,
-        replaced
+        ignored = 0,
+        removed = 1 << 0,
+        added = 1 << 1,
+        replaced = removed | added,
     };
 
     inline float getLength(const osg::Vec2i& value)

From b9b8ed177c389e1d4d65e9664ed7a2931f9dd75b Mon Sep 17 00:00:00 2001
From: elsid <elsid.mail@gmail.com>
Date: Fri, 8 Mar 2019 15:23:36 +0300
Subject: [PATCH 4/7] Store priority values as named fields

---
 .../detournavigator/asyncnavmeshupdater.cpp   | 24 +++++++++----------
 .../detournavigator/asyncnavmeshupdater.hpp   | 11 +++++++--
 2 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/components/detournavigator/asyncnavmeshupdater.cpp b/components/detournavigator/asyncnavmeshupdater.cpp
index fd240e4a0..ce52c1416 100644
--- a/components/detournavigator/asyncnavmeshupdater.cpp
+++ b/components/detournavigator/asyncnavmeshupdater.cpp
@@ -14,16 +14,6 @@ namespace
     {
         return std::abs(lhs.x() - rhs.x()) + std::abs(lhs.y() - rhs.y());
     }
-
-    std::tuple<ChangeType, int, int> makePriority(const TilePosition& position, const ChangeType changeType,
-                                                    const TilePosition& playerTile)
-    {
-        return std::make_tuple(
-            changeType,
-            getManhattanDistance(position, playerTile),
-            getManhattanDistance(position, TilePosition {0, 0})
-        );
-    }
 }
 
 namespace DetourNavigator
@@ -81,8 +71,18 @@ namespace DetourNavigator
         for (const auto& changedTile : changedTiles)
         {
             if (mPushed[agentHalfExtents].insert(changedTile.first).second)
-                mJobs.push(Job {agentHalfExtents, navMeshCacheItem, changedTile.first,
-                                makePriority(changedTile.first, changedTile.second, playerTile)});
+            {
+                Job job;
+
+                job.mAgentHalfExtents = agentHalfExtents;
+                job.mNavMeshCacheItem = navMeshCacheItem;
+                job.mChangedTile = changedTile.first;
+                job.mChangeType = changedTile.second;
+                job.mDistanceToPlayer = getManhattanDistance(changedTile.first, playerTile);
+                job.mDistanceToOrigin = getManhattanDistance(changedTile.first, TilePosition {0, 0});
+
+                mJobs.push(std::move(job));
+            }
         }
 
         log("posted ", mJobs.size(), " jobs");
diff --git a/components/detournavigator/asyncnavmeshupdater.hpp b/components/detournavigator/asyncnavmeshupdater.hpp
index 39898e48e..da9733362 100644
--- a/components/detournavigator/asyncnavmeshupdater.hpp
+++ b/components/detournavigator/asyncnavmeshupdater.hpp
@@ -50,11 +50,18 @@ namespace DetourNavigator
             osg::Vec3f mAgentHalfExtents;
             SharedNavMeshCacheItem mNavMeshCacheItem;
             TilePosition mChangedTile;
-            std::tuple<ChangeType, int, int> mPriority;
+            ChangeType mChangeType;
+            int mDistanceToPlayer;
+            int mDistanceToOrigin;
+
+            std::tuple<ChangeType, int, int> getPriority() const
+            {
+                return std::make_tuple(mChangeType, mDistanceToPlayer, mDistanceToOrigin);
+            }
 
             friend inline bool operator <(const Job& lhs, const Job& rhs)
             {
-                return lhs.mPriority > rhs.mPriority;
+                return lhs.getPriority() > rhs.getPriority();
             }
         };
 

From 82e2739bae198f5854629a1a3a93f2186513f783 Mon Sep 17 00:00:00 2001
From: elsid <elsid.mail@gmail.com>
Date: Fri, 8 Mar 2019 15:27:16 +0300
Subject: [PATCH 5/7] Notify workers when only at least one job is posted

---
 components/detournavigator/asyncnavmeshupdater.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/components/detournavigator/asyncnavmeshupdater.cpp b/components/detournavigator/asyncnavmeshupdater.cpp
index ce52c1416..6cfd75b27 100644
--- a/components/detournavigator/asyncnavmeshupdater.cpp
+++ b/components/detournavigator/asyncnavmeshupdater.cpp
@@ -87,7 +87,8 @@ namespace DetourNavigator
 
         log("posted ", mJobs.size(), " jobs");
 
-        mHasJob.notify_all();
+        if (!mJobs.empty())
+            mHasJob.notify_all();
     }
 
     void AsyncNavMeshUpdater::wait()

From ff47df4f2ccd8ff41d78db6a07ba31793ac7cc34 Mon Sep 17 00:00:00 2001
From: elsid <elsid.mail@gmail.com>
Date: Fri, 8 Mar 2019 15:28:32 +0300
Subject: [PATCH 6/7] Repost navmesh update jobs when failed because of out of
 memory

DT_OUT_OF_MEMORY error is returned when limit of tiles is reached.
---
 .../detournavigator/asyncnavmeshupdater.cpp   | 45 ++++++++++++++-----
 .../detournavigator/asyncnavmeshupdater.hpp   |  9 ++--
 components/detournavigator/makenavmesh.cpp    | 11 ++++-
 components/detournavigator/makenavmesh.hpp    |  9 +++-
 4 files changed, 59 insertions(+), 15 deletions(-)

diff --git a/components/detournavigator/asyncnavmeshupdater.cpp b/components/detournavigator/asyncnavmeshupdater.cpp
index 6cfd75b27..ee3b6d77a 100644
--- a/components/detournavigator/asyncnavmeshupdater.cpp
+++ b/components/detournavigator/asyncnavmeshupdater.cpp
@@ -1,4 +1,4 @@
-#include "asyncnavmeshupdater.hpp"
+#include "asyncnavmeshupdater.hpp"
 #include "debug.hpp"
 #include "makenavmesh.hpp"
 #include "settings.hpp"
@@ -30,6 +30,10 @@ namespace DetourNavigator
                 return stream << "add";
             case UpdateNavMeshStatus::replaced:
                 return stream << "replaced";
+            case UpdateNavMeshStatus::failed:
+                return stream << "failed";
+            case UpdateNavMeshStatus::lost:
+                return stream << "lost";
         }
         return stream << "unknown";
     }
@@ -77,6 +81,7 @@ namespace DetourNavigator
                 job.mAgentHalfExtents = agentHalfExtents;
                 job.mNavMeshCacheItem = navMeshCacheItem;
                 job.mChangedTile = changedTile.first;
+                job.mTryNumber = 0;
                 job.mChangeType = changedTile.second;
                 job.mDistanceToPlayer = getManhattanDistance(changedTile.first, playerTile);
                 job.mDistanceToOrigin = getManhattanDistance(changedTile.first, TilePosition {0, 0});
@@ -104,8 +109,9 @@ namespace DetourNavigator
         {
             try
             {
-                if (const auto job = getNextJob())
-                    processJob(*job);
+                if (auto job = getNextJob())
+                    if (!processJob(*job))
+                        repost(std::move(*job));
             }
             catch (const std::exception& e)
             {
@@ -115,7 +121,7 @@ namespace DetourNavigator
         log("stop process jobs");
     }
 
-    void AsyncNavMeshUpdater::processJob(const Job& job)
+    bool AsyncNavMeshUpdater::processJob(const Job& job)
     {
         log("process job for agent=", job.mAgentHalfExtents);
 
@@ -136,12 +142,16 @@ namespace DetourNavigator
 
         using FloatMs = std::chrono::duration<float, std::milli>;
 
-        const auto locked = job.mNavMeshCacheItem.lockConst();
-        log("cache updated for agent=", job.mAgentHalfExtents, " status=", status,
-            " generation=", locked->getGeneration(),
-            " revision=", locked->getNavMeshRevision(),
-            " time=", std::chrono::duration_cast<FloatMs>(finish - start).count(), "ms",
-            " total_time=", std::chrono::duration_cast<FloatMs>(finish - firstStart).count(), "ms");
+        {
+            const auto locked = job.mNavMeshCacheItem.lockConst();
+            log("cache updated for agent=", job.mAgentHalfExtents, " status=", status,
+                " generation=", locked->getGeneration(),
+                " revision=", locked->getNavMeshRevision(),
+                " time=", std::chrono::duration_cast<FloatMs>(finish - start).count(), "ms",
+                " total_time=", std::chrono::duration_cast<FloatMs>(finish - firstStart).count(), "ms");
+        }
+
+        return isSuccess(status);
     }
 
     boost::optional<AsyncNavMeshUpdater::Job> AsyncNavMeshUpdater::getNextJob()
@@ -194,4 +204,19 @@ namespace DetourNavigator
             *locked = value;
         return *locked.get();
     }
+
+    void AsyncNavMeshUpdater::repost(Job&& job)
+    {
+        if (mShouldStop || job.mTryNumber > 2)
+            return;
+
+        const std::lock_guard<std::mutex> lock(mMutex);
+
+        if (mPushed[job.mAgentHalfExtents].insert(job.mChangedTile).second)
+        {
+            ++job.mTryNumber;
+            mJobs.push(std::move(job));
+            mHasJob.notify_all();
+        }
+    }
 }
diff --git a/components/detournavigator/asyncnavmeshupdater.hpp b/components/detournavigator/asyncnavmeshupdater.hpp
index da9733362..98359964d 100644
--- a/components/detournavigator/asyncnavmeshupdater.hpp
+++ b/components/detournavigator/asyncnavmeshupdater.hpp
@@ -50,13 +50,14 @@ namespace DetourNavigator
             osg::Vec3f mAgentHalfExtents;
             SharedNavMeshCacheItem mNavMeshCacheItem;
             TilePosition mChangedTile;
+            unsigned mTryNumber;
             ChangeType mChangeType;
             int mDistanceToPlayer;
             int mDistanceToOrigin;
 
-            std::tuple<ChangeType, int, int> getPriority() const
+            std::tuple<unsigned, ChangeType, int, int> getPriority() const
             {
-                return std::make_tuple(mChangeType, mDistanceToPlayer, mDistanceToOrigin);
+                return std::make_tuple(mTryNumber, mChangeType, mDistanceToPlayer, mDistanceToOrigin);
             }
 
             friend inline bool operator <(const Job& lhs, const Job& rhs)
@@ -83,13 +84,15 @@ namespace DetourNavigator
 
         void process() throw();
 
-        void processJob(const Job& job);
+        bool processJob(const Job& job);
 
         boost::optional<Job> getNextJob();
 
         void writeDebugFiles(const Job& job, const RecastMesh* recastMesh) const;
 
         std::chrono::steady_clock::time_point setFirstStart(const std::chrono::steady_clock::time_point& value);
+
+        void repost(Job&& job);
     };
 }
 
diff --git a/components/detournavigator/makenavmesh.cpp b/components/detournavigator/makenavmesh.cpp
index a03e9fd8d..e62509940 100644
--- a/components/detournavigator/makenavmesh.cpp
+++ b/components/detournavigator/makenavmesh.cpp
@@ -464,6 +464,15 @@ namespace
             return *this;
         }
 
+        UpdateNavMeshStatusBuilder failed(bool value)
+        {
+            if (value)
+                set(UpdateNavMeshStatus::failed);
+            else
+                unset(UpdateNavMeshStatus::failed);
+            return *this;
+        }
+
         UpdateNavMeshStatus getResult() const
         {
             return mResult;
@@ -531,7 +540,7 @@ namespace
             if (removed)
                 locked->removeUsedTile(changedTile);
             log("failed to add tile with status=", WriteDtStatus {addStatus});
-            return UpdateNavMeshStatusBuilder().removed(removed).getResult();
+            return UpdateNavMeshStatusBuilder().removed(removed).failed((addStatus & DT_OUT_OF_MEMORY) != 0).getResult();
         }
     }
 }
diff --git a/components/detournavigator/makenavmesh.hpp b/components/detournavigator/makenavmesh.hpp
index 20198047c..1dfa242ee 100644
--- a/components/detournavigator/makenavmesh.hpp
+++ b/components/detournavigator/makenavmesh.hpp
@@ -26,8 +26,15 @@ namespace DetourNavigator
         removed = 1 << 0,
         added = 1 << 1,
         replaced = removed | added,
+        failed = 1 << 2,
+        lost = removed | failed,
     };
 
+    inline bool isSuccess(UpdateNavMeshStatus value)
+    {
+        return (static_cast<unsigned>(value) & static_cast<unsigned>(UpdateNavMeshStatus::failed)) == 0;
+    }
+
     inline float getLength(const osg::Vec2i& value)
     {
         return std::sqrt(float(osg::square(value.x()) + osg::square(value.y())));
@@ -41,7 +48,7 @@ namespace DetourNavigator
     inline bool shouldAddTile(const TilePosition& changedTile, const TilePosition& playerTile, int maxTiles)
     {
         const auto expectedTilesCount = std::ceil(osg::PI * osg::square(getDistance(changedTile, playerTile)));
-        return expectedTilesCount * 3 <= maxTiles;
+        return expectedTilesCount <= maxTiles;
     }
 
     NavMeshPtr makeEmptyNavMesh(const Settings& settings);

From f2e47d640d15dc5b1e96f34dd1ca18245ad8d0b0 Mon Sep 17 00:00:00 2001
From: elsid <elsid.mail@gmail.com>
Date: Fri, 22 Feb 2019 01:22:10 +0300
Subject: [PATCH 7/7] Add option to limit max number of navmesh tiles

---
 .../detournavigator/navigator.cpp             |  1 +
 components/detournavigator/makenavmesh.cpp    |  2 +-
 components/detournavigator/navmeshmanager.cpp |  2 +-
 components/detournavigator/settings.cpp       |  1 +
 components/detournavigator/settings.hpp       |  1 +
 .../reference/modding/settings/navigator.rst  | 24 +++++++++++++++++++
 files/settings-default.cfg                    |  3 +++
 7 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/apps/openmw_test_suite/detournavigator/navigator.cpp b/apps/openmw_test_suite/detournavigator/navigator.cpp
index 42b69d7f9..9daef6f64 100644
--- a/apps/openmw_test_suite/detournavigator/navigator.cpp
+++ b/apps/openmw_test_suite/detournavigator/navigator.cpp
@@ -61,6 +61,7 @@ namespace
             mSettings.mMaxSmoothPathSize = 1024;
             mSettings.mTrianglesPerChunk = 256;
             mSettings.mMaxPolys = 4096;
+            mSettings.mMaxTilesNumber = 512;
             mNavigator.reset(new NavigatorImpl(mSettings));
         }
     };
diff --git a/components/detournavigator/makenavmesh.cpp b/components/detournavigator/makenavmesh.cpp
index e62509940..5ac28127e 100644
--- a/components/detournavigator/makenavmesh.cpp
+++ b/components/detournavigator/makenavmesh.cpp
@@ -628,7 +628,7 @@ namespace DetourNavigator
             return removeTile();
         }
 
-        if (!shouldAddTile(changedTile, playerTile, params.maxTiles))
+        if (!shouldAddTile(changedTile, playerTile, std::min(settings.mMaxTilesNumber, params.maxTiles)))
         {
             log("ignore add tile: too far from player");
             return removeTile();
diff --git a/components/detournavigator/navmeshmanager.cpp b/components/detournavigator/navmeshmanager.cpp
index 2a29d1dd4..217c17e41 100644
--- a/components/detournavigator/navmeshmanager.cpp
+++ b/components/detournavigator/navmeshmanager.cpp
@@ -157,7 +157,7 @@ namespace DetourNavigator
                 if (changedTiles->second.empty())
                     mChangedTiles.erase(changedTiles);
             }
-            const auto maxTiles = navMesh.getParams()->maxTiles;
+            const auto maxTiles = std::min(mSettings.mMaxTilesNumber, navMesh.getParams()->maxTiles);
             mRecastMeshManager.forEachTilePosition([&] (const TilePosition& tile)
             {
                 if (tilesToPost.count(tile))
diff --git a/components/detournavigator/settings.cpp b/components/detournavigator/settings.cpp
index ddffd0d1f..735194dba 100644
--- a/components/detournavigator/settings.cpp
+++ b/components/detournavigator/settings.cpp
@@ -24,6 +24,7 @@ namespace DetourNavigator
         navigatorSettings.mMaxEdgeLen = ::Settings::Manager::getInt("max edge len", "Navigator");
         navigatorSettings.mMaxNavMeshQueryNodes = ::Settings::Manager::getInt("max nav mesh query nodes", "Navigator");
         navigatorSettings.mMaxPolys = ::Settings::Manager::getInt("max polygons per tile", "Navigator");
+        navigatorSettings.mMaxTilesNumber = ::Settings::Manager::getInt("max tiles number", "Navigator");
         navigatorSettings.mMaxVertsPerPoly = ::Settings::Manager::getInt("max verts per poly", "Navigator");
         navigatorSettings.mRegionMergeSize = ::Settings::Manager::getInt("region merge size", "Navigator");
         navigatorSettings.mRegionMinSize = ::Settings::Manager::getInt("region min size", "Navigator");
diff --git a/components/detournavigator/settings.hpp b/components/detournavigator/settings.hpp
index 0316092a0..dc0e5dc5a 100644
--- a/components/detournavigator/settings.hpp
+++ b/components/detournavigator/settings.hpp
@@ -26,6 +26,7 @@ namespace DetourNavigator
         int mMaxEdgeLen = 0;
         int mMaxNavMeshQueryNodes = 0;
         int mMaxPolys = 0;
+        int mMaxTilesNumber = 0;
         int mMaxVertsPerPoly = 0;
         int mRegionMergeSize = 0;
         int mRegionMinSize = 0;
diff --git a/docs/source/reference/modding/settings/navigator.rst b/docs/source/reference/modding/settings/navigator.rst
index 1b65c35a8..d9ddf5381 100644
--- a/docs/source/reference/modding/settings/navigator.rst
+++ b/docs/source/reference/modding/settings/navigator.rst
@@ -24,6 +24,24 @@ Moving across external world, entering/exiting location produce nav mesh update.
 NPC and creatures may not be able to find path before nav mesh is built around them.
 Try to disable this if you want to have old fashioned AI which doesn't know where to go when you stand behind that stone and casting a firebolt.
 
+max tiles number
+----------------
+
+:Type:		integer
+:Range:		>= 0
+:Default:	512
+
+Number of tiles at nav mesh.
+Nav mesh covers circle area around player.
+This option allows to set an explicit limit for nav mesh size, how many tiles should fit into circle.
+If actor is inside this area it able to find path over nav mesh.
+Increasing this value may decrease performance.
+
+.. note::
+    Don't expect infinite nav mesh size increasing.
+    This condition is always true: ``max tiles number * max polygons per tile <= 4194304``.
+    It's a limitation of `Recastnavigation <https://github.com/recastnavigation/recastnavigation>`_ library.
+
 Advanced settings
 *****************
 
@@ -322,6 +340,12 @@ Maximum number of polygons per nav mesh tile. Maximum number of nav mesh tiles d
 this value. 22 bits is a limit to store both tile identifier and polygon identifier (tiles = 2^(22 - log2(polygons))).
 See `recastnavigation <https://github.com/recastnavigation/recastnavigation>`_ for more details.
 
+.. Warning::
+    Lower value may lead to ignored world geometry on nav mesh.
+    Greater value will reduce number of nav mesh tiles.
+    This condition is always true: ``max tiles number * max polygons per tile <= 4194304``.
+    It's a limitation of `Recastnavigation <https://github.com/recastnavigation/recastnavigation>`_ library.
+
 max verts per poly
 ------------------
 
diff --git a/files/settings-default.cfg b/files/settings-default.cfg
index e3920a4bf..e95646602 100644
--- a/files/settings-default.cfg
+++ b/files/settings-default.cfg
@@ -670,6 +670,9 @@ enable nav mesh render = false
 # Render agents paths (true, false)
 enable agents paths render = false
 
+# Max number of navmesh tiles (value >= 0)
+max tiles number = 512
+
 [Shadows]
 
 # Enable or disable shadows. Bear in mind that this will force OpenMW to use shaders as if "[Shaders]/force shaders" was set to true.